254 
Browne . — The Anatomy of the 
already stated, both my specimens had eleven bundles ; moreover, from the 
structure at the base of Cones B and D it is clear that the latter cones were 
borne on axes with eleven bundles. In Cones A and B, however, one of 
the bundles was very small and poorly lignified. In Cone C there are ten 
internodal strands presumably arising above and between an equal number 
of leaves. 
The U-shaped or horseshoe-like distribution of the tracheides in the 
bundles does not always persist for any considerable distance. Sometimes 
the lateral arms flatten out rapidly as we pass upwards. The more 
internally situated elements may come to lie in the continuation of the 
curve, slightly concave outwards, formed bythecarinal group of tracheides, 
while the peripheral elements may cease to develop as tracheides. In other 
cases there is, for a short distance, no lateral metaxylem, so that, most of 
the protoxylem having disappeared, the mature stem may possess very 
little xylem at this level. If the U-shaped distribution of the xylem is 
temporarily lost, it is restored below the insertion of the annulus ; in other 
cases the xylem of each bundle remains more or less U-shaped, until just 
below the point at which the annulus becomes free from the axis. At this 
level the xylem assumes the compact form characteristic of the bundles of 
the cone. Between the annulus and the last whorl of leaves the bundles 
not infrequently contain one to four, commonly two or three, rather wide 
tracheides adherent to the inner wall of the carinal canal. In other words, 
the first elements to be destroyed by the formation of the carinal canal are 
not the most internally situated. Developmental stages were not available, 
but it seems possible that these elements may have been centripetal xylem 
(cf. PI. VIII, Figs. 3, 4, 7, and 9). Below the annulus the bundles not infre- 
quently contain one or more laterally situated tracheides much larger than 
the others. 
The annulus is adherent to the stem by its wide base, giving the latter 
a funnel-shaped outline. The free edge is slightly incurved and appears to 
be normally sporangiferous (PI. VIII, Fig. 2). The sporangia, which are 
about half the size of those borne by the sporangiophores, are completely 
hidden by the incurved edge of the annulus, and no trace of them was 
observable until the cones had been sectioned. In all the specimens 
examined the annulus contained a certain number of vascular bundles 
running to the insertion of the sporangia. These are attached by their 
upper ends to the incurved edge of the annulus. Not all of the vascular 
bundles are connected with axial strands ; as a rule the greater number, 
sometimes all of them, die out without reaching the axial stele. Such 
bundles may conveniently be described as free (annular) bundles. They 
are shown in the reconstructions, black on white and white on black, on the 
bundles and parenchymatous meshes on the radii of which they die out. 
In the reconstruction of Cone A they are distinguished from the traces 
